To secure enough electricity supply into western Japan around Osaka and Kyoto during summer demand season, Kansai Electric Power Company may resume No. 3 and No. 4 reactors at its Oi nuclear power plant in the near future.
Regional local governments and the central government are expected to approve the restart. Meanwhile, possibility of large power outage forces opponents to be silence.
KEPCO is not able to meet electricity demand during the summer season without nuclear power supply. Since the two reactors will add nearly 2.4 million kilowatts of output capacity, the company can avoid serious shortage of power supply.
On the other hand, Tokyo Electric Power Company earlier said it is likely to supply enough electricity without nuclear power output even if under the heat wave conditions.
What causes difference between KEPCO and TEPCO?
We can find a part of the reason when watch the change in power output sources by each company over the past decade.
TEPCO and CHUBU Electric Power have increased their thermal power output capacity, while KEPCO has deepened dependent on nuclear power. KEPCO also seemed not to eager to upgrade thermal power facilities.
Breakdown of thermal power output capacity by fuel describes that liquefied natural gas is accounting for more than 60% of total thermal power generation capacity at TEPCO and CHUBU, while their old fashion petroleum-burning output capacity remains less than 30% of the total. But petroleum-burning output capacity is the biggest part for KEPCO's thermal power facilities.
Since very few petroleum-burn thermal power plants have been constructed in Japan after mid-1980's, more than half of KEPCO's thermal power units are aging facilities.
However, the poor thermal power output facilities is not only because of KEPCO. Japanese government has encouraged utility firms to develop nuclear power. Also global warming has pressured power companies to reduce carbon dioxide emission.
The reason why TEPCO has expanded its thermal power output despite such social environment was unexpected errors.
The company caused a scandal about faked maintenance records of nuclear power plants. After the revelation of the scandal in 2002, TEPCO's executives were forced to resign and its all nuclear power units were forced to shut for examination.
Then a heavy earthquake in central Japan in 2007 forced TEPCO's Kashiwazaki-Kariwa nuclear power plants to shut for long period.
Because of these serious nuclear power supply shortage, the company has been keen to secure alternative power supply sources.
CHUBU scrapped two reactors at its Hamaoka nuclear power plant in 2009 as there was no economic reason to spend huge amount of money to strengthen those old facilities. Since the company has no spare location to build fresh nuclear plants, it has increased thermal power output capacity.
In contrast to those, KEPCO has not had serious problem over its nuclear plants. The above chart shows KEPCO's stable nuclear power supply compared to TEPCO.
KEPCO seemed not to feel the TEPCO's scandal as their own affair because the company uses pressurized water reactor different from boiling water reactor which is used by TEPCO and CHUBU.
Seven out of the total 11 reactors owned by KEPCO are old facilities that started operation in 1970's. Their useful lifetime had finished long time ago. However, extending was not difficult supported by overconfidence over the safety of nuclear power plants. It was not only cost efficient compared to building new thermal power plants but was thought useful for global warming issue.
Over 40 years old reactors, however, are likely to be abolished as well as Hamaoka. Extending further to 50 years and 60 years without recognizing the aging is not realistic, especially in the earthquake-prone area like Japan.
Thus considering to build advanced thermal power units and new fuel unloading facilities is urgently required for KEPCO. Possible growth of electricity demand and troubles over aged thermal plants may urge it. But open discussion about such direction is not heard much.